1. Field of Invention
This invention relates to a hyperbaric chamber. Specifically, the invention describes a human hyperbaric chamber and airlock system that is lightweight, portable, stowable and collapsible. It provides the atmospheric pressures (over two atmospheres) required for standard hyperbaric medical treatments, including both hypobaric and hyperbaric decompression sickness. The device can be sized to contain at least one patient and attending medic(s).
2. Background Information and Related Art
Humans can experience altered atmospheric pressures in several environments (aviation, submarine operations, spacecraft, extravehicular space activities, scuba diving, etc.) Decompression sickness can develop under these conditions, occasionally leading to serious or fatal injury. Hyperbaric chambers are successfully used to treat decompression sickness.
Conventional hyperbaric chambers, made of solid metal, are heavy, have permanently high volume, and are not readily portable. For remote operational environments (International Space Station; civilian, commercial and military diving operations), conventional hyperbaric treatment chambers are often unavailable because of their lack of portability. A lightweight, portable, collapsible chamber would provide much-needed decompression sickness treatment capability in remote areas without great weight or stowage penalties. Currently, portable chamber designs exist, but often can not provide maximum standard therapy due to structural and pressure limitations. Their lack of an integral airlock prohibits access to the pressurized patient, thereby markedly decreasing the level of safety and treatment flexibility. Current portable chambers either have a permanent rigid skeleton (which dramatically increases storage volume), or lack internal support (which makes access extremely difficult and unpleasant when the chamber is not pressurized.) Many currently available collapsible chambers are sized for only one occupant (the patient), which limits the ability to treat and care for the patient.
Prior art for flexible hyperbaric chambers includes that described by Santi in U.S. Pat. No. 5,738,093. The present invention differs from the Santi patent in several important respects. First, in Santi the hatch is closed by rotating the hatch engaging threaded sectors. When pressurized, this places a heavy pressure load on the hatch threads, requiring the hatch and supporting structures to be very heavy. Second, the longitudinal and hoop straps supporting the chamber bladder are designed to have large spaces between the straps, requiring the chamber bladder to have a high strength and thickness in order to prevent billowing through the web spaces. Third, the straps are terminated at each end by looping the strap through a slot in a thin metallic fitting and stitching the strap onto itself. The thin metallic fittings are then bolted to the end rings. The slot in the thin metallic fitting forces the webbing to bend in a sharp radius that a) causes a high local stress in the straps, creating potential failure points and reducing the safety margins and b) creates high friction at the interface of the webbing and the thin metallic fitting, causing uneven load sharing between the outside of the loop and the inside of the loop. Fourth, the feed-through provisions for air, instrumentation wiring, pressurization etc. are located in the hatch itself, creating very cumbersome hatch operations due to the restrictive nature of the attached lines to the hatch.
Other examples of inflatable chambers include patents by Cardwell as disclosed in U.S. Pat. No. 5,255,673 and Bleiken in U.S. Pat. No. 3,602,221. Both devices lack any type of internal structural support before they are sealed and pressurized. Thus, when the patient is first placed in the collapsed device, part of the device is lying on top of him. These conditions make positioning the patient and equipment inside the device very difficult, poses a possible suffocation exposure, and can induce dangerous anxiety in claustrophobic individuals. Further, these and other typical prior art inflatable chambers are designed for only one occupant, making the presence of a medical attendant impossible.
The sealing systems for prior art inflatable chambers have various limitations. Some, such as disclosed by Miller in U.S. Pat. No. 3,729,002, use a zipper and seal system which is zipped and then reinforced by a loop and rod system inserted externally. Such a system creates high local stresses in the flexible fabric, which must therefore be heavy and bulky.
It would thus be a new and useful improvement to a portable hyperbaric chamber to accomplish the above-described purposes without the limitations of the prior art.